decay.c File Reference

Factors for correcting or simulating physical decay. More...

#include "tpcclibConfig.h"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <string.h>
#include "tpcisotope.h"

Go to the source code of this file.

Functions
char *	decayDescr (decaycorrection d)
double	lambdaFromHalflife (double halflife)
double	lambdaFromIsotope (int isotope)
double	decayCorrectionFactorFromLambda (double lambda, double starttime, double duration)
double	decayCorrectionFactorFromIsotope (int isotope, double starttime, double duration)

Detailed Description

Factors for correcting or simulating physical decay.

Definition in file decay.c.

Function Documentation

decayCorrectionFactorFromIsotope()

double decayCorrectionFactorFromIsotope	(	int	isotope,
		double	starttime,
		double	duration )

Calculate the correction factor for physical decay from measurement time to time zero.

Returns

Factor for decay correction (>1), or NaN if input is invalid.

See also

lambdaFromIsotope, isotopeIdentify, decayCorrectionFactorFromLambda, isotopeName

Author

Vesa Oikonen

Parameters

isotope	isotope_code as enum or the index of isotope in isotope table.
starttime	Radioactivity measurement start time, or middle time, if measurement duration is not known. Unit must be min.
duration	Radioactivity measurement duration; if not known, then set to zero, and put measurement middle time for starttime. Unit must be min.

Definition at line 107 of file decay.c.

  {
  double lambda=lambdaFromIsotope(isotope); if(isnan(lambda)) return nan("");
  return decayCorrectionFactorFromLambda(lambda, starttime, duration);
}

Referenced by noiseSD4Frame(), and sifWeight().

decayCorrectionFactorFromLambda()

double decayCorrectionFactorFromLambda	(	double	lambda,
		double	starttime,
		double	duration )

Calculate the correction factor for physical decay from measurement time to time zero.

Returns

Factor for decay correction (>1 when lambda>0) or for simulating decay (<1 when lambda<0), or NaN if input is invalid.

See also

lambdaFromIsotope, isotopeIdentify, decayCorrectionFactorFromIsotope

Author

Vesa Oikonen

Parameters

lambda	Positive or negative lambda for the isotope. Note that time unit must be 1/timeunit of the starttime and duration.
starttime	Radioactivity measurement start time, or middle time, if measurement duration is not known.
duration	Radioactivity measurement duration; if not known, then set to zero, and put measurement middle time for starttime.

Definition at line 79 of file decay.c.

  {
  if(starttime<0.0) return nan("");
  if(duration<0.0) duration=0.0;
  if(fabs(lambda)<1.0E-100) return nan("");
  double cf=exp(lambda*starttime);
  if(duration>1.0E-10) {
    double ff=fabs(lambda)*duration/(1.0-exp(-fabs(lambda)*duration));
    if(lambda<0.0) cf/=ff; else cf*=ff;
  }
  return(cf);
}

Referenced by decayCorrectionFactorFromIsotope(), tacDecayCorrection(), and tacWByFreq().

decayDescr()

char * decayDescr

(

decaycorrection

d

)

Return pointer to string describing the status of decay correction.

See also

isotopeName

Returns

pointer to the name string.

Parameters

d	Enum decaycorrection.

Definition at line 32 of file decay.c.

  {
  if(d>4) return(decay_correction[0]);
  return(decay_correction[d]);
}

Referenced by dcmImgIsotope(), and imgReadDICOM().

lambdaFromHalflife()

double lambdaFromHalflife

(

double

halflife

)

Calculate lambda based on specified halflife.

Returns

Lambda (=ln(2)/halflife), or NaN if halflife is NaN or <=0.

See also

isotopeIdentifyHalflife, isotopeName, lambdaFromIsotope

Author

Vesa Oikonen

Parameters

halflife

Halflife of the isotope; if halflife is in minutes, then the unit of lambda will be 1/min, if seconds, then lambda will be in units 1/sec, etc.

Definition at line 47 of file decay.c.

  {
  if(halflife>0.0) return(M_LN2/halflife);  // M_LN2=log(2.0)
  else return nan("");
}

Referenced by tacDecayCorrection().

lambdaFromIsotope()

double lambdaFromIsotope

(

int

isotope

)

Calculate lambda for specified isotope.

Returns

Lambda (=ln(2)/halflife) in units 1/min, or NaN if isotope is not identified.

See also

decayCorrectionFactorFromLambda, isotopeName, isotopeIdentify, decayCorrectionFactorFromIsotope

Author

Vesa Oikonen

Parameters

isotope

isotope_code as enum or the index of isotope in isotope table.

Definition at line 63 of file decay.c.

  {
  double hl=isotopeHalflife(isotope); if(isnan(hl) || hl<=0.0) return nan("");
  return(M_LN2/hl);
}

Referenced by decayCorrectionFactorFromIsotope(), and tacWByFreq().